Highly enhanced ferroelectricity in HfO ₂ -based ferroelectric thin film by light ion bombardment

Abstract

Continuous advancement in nonvolatile and morphotropic beyond-Moore electronic devices requires integration of ferroelectric and semiconductor materials. The emergence of hafnium oxide (HfO 2 )–based ferroelectrics that are compatible with atomic-layer deposition has opened interesting and promising avenues of research. However, the origins of ferroelectricity and pathways to controlling it in HfO 2 are still mysterious. We demonstrate that local helium (He) implantation can activate ferroelectricity in these materials. The possible competing mechanisms, including He ion–induced molar volume changes, vacancy redistribution, vacancy generation, and activation of vacancy mobility, are analyzed. These findings both reveal the origins of ferroelectricity in this system and open pathways for nanoengineered binary ferroelectrics.

Structural and Electrical Response of Emerging Memories Exposed to Heavy Ion Radiation

“…Such a recovery of ferroelectric properties induced by cycling has been reported in literature for fatigued, nonirradiated PZT and HfO x -based ferroelectric films. Additionally, a comparable enhancement of the polarization in HfO 2 thin films by light ion He bombardment was recently reported . The main difference to the presented experiments is the use of light He ions with a much lower electronic energy loss than obtained for 1.635 GeV Au ions.…”

“…Additionally, a comparable enhancement of the polarization in HfO 2 thin films by light ion He bombardment was recently reported. 71 The main difference to the presented experiments is the use of light He ions with a much lower electronic energy loss than obtained for 1.635 GeV Au ions. This is leading to a different interaction and damage process.…”

“…Further, no evidence for changes of the electrical properties and crystalline phase were found in stacks containing ferroelectric hafnium oxide-based films after proton irradiation at huge fluences of 10 15 protons/cm 2 . , This is not a contradiction to our observation but a direct indication that the energy loss of protons is too low to initiate a phase transition in HfZrO 2 films. Still, material property changes, like an increase of the polarization, can be induced in HfO 2 -based ferroelectrics, which are based on nuclear interaction and ion implantation . Overall, working devices showing distinct polarization states even at rather high energies and fluences as well as polarization recovery by postcycling directly suggest that ferroelectric memories based on hafnium oxide films are radiation-hard.…”

“…Still, material property changes, like an increase of the polarization, can be induced in HfO 2 -based ferroelectrics, which are based on nuclear interaction and ion implantation. 71 Overall, working devices showing distinct polarization states even at rather high energies and fluences as well as polarization recovery by postcycling directly suggest that ferroelectric memories based on hafnium oxide films are radiation-hard.…”

Exploring Physics of Ferroelectric Domain Walls in Real Time: Deep Learning Enabled Scanning Probe Microscopy

“…Over the last decade, the field of ferroelectric materials has been significantly broadened by the discovery of ferroelectric phenomena in new materials classes, most notably binary oxides such as hafnia and zirconia and their solid solutions; [ 8 , 9 , 10 , 11 , 12 ] scandium, boron, and aluminum nitrides; [ 13 , 14 , 15 , 16 , 17 ] and zinc‐magnesium oxides. [ 18 , 19 ] These discoveries have both changed the extant paradigms on mechanisms underpinning ferroelectricity, and open the pathway to a broad range of information technology device applications.…”